The long-term objective of this research is to develop and test a variety of methods to investigate effects of linguistic and extralinguistic context on responses obtained when children's linguistic skills are being assessed. The immediate objective is to develop and pilot such methods using a smll group of children and one important language concept--the temporal relation "before/after". English is linguistically compulsive about expressions of time, and at least one investigator of child language has proposed that the development of temporal concepts should serve as a model for studying the acquisition of abstract ideas. "Before/after" has received much attention in recent experimental studies using both adult and child subjects. Different experimenters asking what appear to be similar questions have often obtained very different and sometimes contradictory results. It is argued that these diverse findings may be largely attributable to contextual variation, both linguistic and extralinguistic. The general strategy of the research proposed will be to examine performance of the same group of children in two situations--in a naturalistic setting and in the laboratory, and doing so for both production and comprehension. Influences of pragmatic as well as syntactic and semantic variables will be studied at the time when children are mastering these particular temporal relations. Data from the same children in different contexts should dissuade theorists from discussing whether or not a child "has" the concept. Instead, the results should force one to account for the effects on contextual variations in terms of the specific cognitive operations that a child performs (or failed to perform) in each situation.